I present here the best, most economical way --IMHO-- to send chips through the mail if:
(1) the chips are sturdy and relatively inexpensive (that is, you are not too concerned about cushioning the chips) -- like a modern casino chip.
(2) the total weight of the chips and envelope is no more than 3.5 ounces (so you can use the first class "letter" rate).
(3) you have a relatively low volume of outgoing chip mail. (If you are constantly sending chips through the mail, use corrugated adhesive paper or Cro-nel, to save time and still be able to send the stuff "letter" rate.)

Here is how I mail three INEXPENSIVE, MODERN, STURDY 14-gram chips for $0.79. I send them via first class LETTER rate (because the end product is no more than than 1/4" thick). I use a small regular envelope (6-1/2" x 3-1/2"). I include a half sheet of paper for my note and a business card. It ends up weighing just under 2 ounces. Again, the cost is $0.79 ($0.42 [first ounce] + $0.17 [second ounce] + $0.20 [surcharge because the envelope will be rigid]). I have never had a problem in any way (with the post office or chip breakage), and I have sent many chips this way.

I sandwich the chips side-by-side between a folded piece of cereal-type cardboard. I tape the edges of this package of cardboard and chips. Then I tape this package to the inside back of the envelope (so nothing slides about)! Then I insert the half sheet of paper note and a business card. Then I seal and tape the envelope. Pictures below.

If these three chips were sent either (1) loose in a bubble wrap mailer, or (2) sandwiched between thick cardboard in a regular envelope, the mailpiece would likely be classified as a "first class parcel," would weigh over 2 ounces, and would cost $1.51 in postage. (It wouldn't be classified as a "first class flat (large envelope)" because of the bubble wrap envelope and/or the non-flexibility and non-uniform thickness.)

(I suppose that if you have a lot of outgoing mail, it might be better [time and labor-wise] to pay more and use bubble envelopes. And I wouldn't mail an antique poker chip the $0.79-way I present above; rather, I would sandwich it between two thick pieces of strong cardboard, and mail it as a "first class parcel.")

Robert